Method of electroslag melting of semiannular metallic ingot

ABSTRACT

A method of the electroslag melting of a semiannular metallic ingot by remelting a blank having a shape of an unclosed ring with one end of the blank being fastened to a dummy bar and the other end being immersed into a pool of molten slag. As the blank is melted off, it is rotated together with the dummy bar about a horizontal axis in the direction in which the ingot is withdrawn with a speed equal to that of its building-up.

' United StatesPatent [191 I Medovar et al.

[ Jan. 21, 1975 METHOD OF ELECTROSLAG MELTING OF SEMIANNULAR METALLIC lNGOT Inventors: Boris lzrailevich Medovar, bulvar Lesi Ukrainki 2, kv. 8; Rudolf Solomonovich Dubinsky, ulitsa Politekhnicheskaya 5, kv. 29; Valery Alexandrovich Prikhodko, bulvar Davydova 7, kv. 158; Ilya losifovich Kumysh, Vozdukhoflotsky prospekt, 42, kv. 51, all of Kiev, U.S.S.R.

Filed: Apr. 17, 1973 Appl. No.2 351,992

US. Cl. 164/52, 164/92 Int. Cl 822d 27/02 Field of Search 164/52, 252, 50, 85, 92

References Cited UNITED STATES PATENTS Dick 219/137 3,785,429 l/1974 Ujiie l64/252 X Primary Examiner-Andrew R. Julmsz Assistant Examiner-John E. Rocthcl Attorney, Agent, or FirmHolman & Stern [57] ABSTRACT 4 Claims, 2 Drawing Figures 1 METHOD OF ELECTROSLAG MELTING OF SEMIANNULAR METALLIC INGOT BACKGROUND OF THE INVENTION The present invention relates to methods of the electro-slag melting of semiannular metallic ingots which may prove to be most advantageous as blanks for producing pressure vessels and shroud rings for cement kilns.

In the present state of the art such blanks are fabricated by forging and welding.

A method of melting hollow cylindrical metallic ingots by the electroslag process is well known in the art which envisages the melting of consumable electrodes and shaping an ingot in a circular gap between the internal wall of a cylindrical cooled mould and a cooled mandrel accommodated in the mould and adapted for shaping the ingot space. The above method is suitable for the production of metal ingots, up to l m. in diameter. However, this prior-art method is economically impracticable for manufacturing heavier ingots, insofar as it requires sophisticated equipment and high-power power supply sources.

There are cooled moulds with a radially curved portion for shaping a metallic ingot known in the art, which find use in radial continuous casting machines, for instance, for casting steel. In the above machines the curvature of the ingot being withdrawn is a quarter ofa circle, with the ingot being straightened thereupon.

The use of the radially curved cooled moulds in the plants for producing metallic ingots by the electroslag remelting process is not known as yet. Usually in melting the ingot by the electroslag process use is made of the moulds having a longitudinal axis in the section, where the ingot is shaped and into which a dummy bar is introduced prior to starting the process, and an enlarged section in the zone ofa molten slag bath wherein the ingot to be remelted (a consumable electrode) is inserted whereupon an electric current is passed from a power source to the dummy bar and the consumable electrode and the molten slag is poured until the current of a preset magnitude is obtained. Occasionally, the blank is remelted by using a non-consumable electrode.

Thus, there is no economically expedient method of producing hollow ingots more than 1 m. in diameter, which presents certain problems.

SUMMARY OF THE INVENTION The main object of the present invention is to provide a method of the electroslag melting of semiannular metallic ingots which may be used as blanks for manufacturing pressure vessels and shroud rings for cement kilns.

Another important object of the invention is the use of compact equipment and medium-power transformers for accomplishing the above method.

Still another object of the invention is the remelting (renovation) of used shells more than 1 m. in diameter which have been in service and feature certain defects.

These and other objects are accomplished by the provision of a method of the electroslag melting of a semiannular metallic ingot comprising the steps of introducing a dummy bar into a mould part adapted to shape the ingot, inserting one of the ends of the blank to be remelted into the enlarged mould part, supplying electric current from a power source and pouring molten slag until an electric current of a preset magnitude is obtained, wherein, according to the invention, a blank in the form of an unclosed ring is subject to remelting with the other end of the blank being fastened to the dummy bar and rotated in the direction in which the ingot is withdrawn with a speed equal to that of ingot building-up.

The method will enable the production of the semiannular ingots more than I m. in diameter which may be welded to produce annular blanks suitable for manufacturing articles, such as, pressure vessels and shroud rings for cement kilns.

The blank being remelted is desirable to rotate together with the dummy bar about a horizontal axis.

It is preferable that rotation of the blanks being remelted be effected about the horizontal axis. However, the plane of rotation of the blanks may deflect from a perpendicular by 5-l0.

The blank being remelted may be connected to a power source to be used as a consumable electrode. This will enable the process to be conducted without using an additional consumable electrode.

It is expedient that for remelting the blank the nonconsumable electrode connected to the power source be used.

This will make it possible to eliminate electric insulation between the dummy bar and the blank being remelted and to avoid the need for a device for supplying electric current to the blank being remelted.

BRIEF DESCRIPTION OF THE DRAWINGS The invention is further exemplified by a detailed description of specific embodiments thereof, when read in conjunction with the accompanying drawings, wherein:

FIG. 1 is a diagrammatic representation of the electroslag remelting of a semiannular ingot when the blank to be remelted in the form of an unclosed ring is employed as a consumable electrode; and

FIG. 2 is a diagrammatic representation of the process of melting a similar ingot by using a nonconsumable electrode.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS At the beginning of the melting process, one of the ends 1 (FIG. 1) of the blank 2 being remelted made as an unclosed ring is connected through electric insulation 3 to a dummy bar 4. Then the dummy bar 4 is introduced into the part 6 of a mould 7, the part being adapted to shape a metallic ingot 5, whereas the other end 8 of the blank 2 being remelted is inserted into an enlarged part 9 of the mould 7.

The dummy bar 4 and the blank 2 being remelted are connected to a power supply source 10 and voltage is applied across them.

Following that, molten slag 11 is poured into the enlarged part 9 of the mould 7 until electric current starts flowing through the blank being remelted dummy bar circuit.

Under the effect of the temperature of the molten slag 11 the blank 2 melts off into molten metal 12 which is shaped into the ingot 5 in the part 6 of the mould 7.

As the ingot 5 is built-up, the blank 2 being remelted is rotated together with the ingot 5 about a horizontal axis 13 passing through the center point of the blank 2 being remelted, having the form of an unclosed ring and being traversed along the circumference whose axis is coincident with the longitudinal axis of the blank 2 being remelted. The blank 2 being remelted is rotated in the direction in which the ingot is withdrawn with a speed equal to that of the ingot building-up (withdrawal).

An end 1 of the blank 2 being remelted (FIG. 2) is connected to a dummy bar 4 without using electric insulation. A non-consumable electrode 14 and the dummy bar 4 are coupled to a power supply source 10.

As the blank 2 to be remelted is being melted off and ingot 5 is built-up, the latter is withdrawn from the part 6 of the mould 7, the blank 2 to be remelted being fed into the enlarged part 9 of the mould 7 and rotated concurrently with the part about the horizontal axis 13 along a common for them circumference whose radius conforms to a radius of curvature of the blank 2 being remelted and ingot 5 being built-up.

The plane of rotation of the blank 2 being remelted may form an angle of 5-l0 with a vertical, with the axis of rotation being deflected from a horizontal at a similar angle.

In order to embody the herein-proposed method, simple and compact equipment is utilized, the circuit being powered from a medium-power current supply source.

The above method will allow melting shells for the purpose of enhancing quality of metal and eliminating defects on their surface.

What we claim is:

l. A method of the electroslag melting ofa semiannular metallic ingot in a cooled mould having an enlarged part to accommodate metal and slag bath and a part adapted to shape the metallic ingot, said method comprising the steps of: introducing a dummy bar into the mould part adapted to shape the metal ingot; fastening one of the ends of a blank being remelted having the form of an unclosed ring to the dummy bar, the other end of the blank being immersed into the enlarged part of the mould; applying voltage fed from a power supply source across the dummy bar and an element acting as an electrode; pouring slag into the enlarged part of the mould until an electric current of a preset magnitude is obtained; and rotating the blank being remelted in a direction in which the ingot is withdrawn and with a speed equal to that of its building-up.

2. A method as claimed in claim 1, wherein said step of rotating blank being remelted and fastened to the dummy bar includes rotating the blank and the dummy bar about a horizontal axis.

3. A method as claimed in claim 1, further includes the step of connecting a power supply source to the blank being remelted, the blank being employed as a consumable electrode.

4. A method as claimed in claim 1, further includes the step of connecting a power supply source to the blank being remelted by way ofa non-consumable electrode being coupled to the power supply. 

1. A method of the electroslag melting of a semiannular metallic ingot in a cooled mould having an enlarged part to accommodate metal and slag bath and a part adapted to shape the metallic ingot, said method comprising the steps of: introducing a dummy bar into the mould part adapted to shape the metal ingot; fastening one of the ends of a blank being remelted having the form of an unclosed ring to the dummy bar, the other end of the blank being immersed into the enlarged part of the mould; applying voltage fed from a power supply source across the dummy bar and an element acting as an electrode; pouring slag into the enlarged part of the mould until an electric current of a preset magnitude is obtained; and rotating the blank being remelted in a direction in which the ingot is withdrawn and with a speed equal to that of its building-up.
 2. A method as claimed in claim 1, wherein said step of rotating blank being remelted and fastened to the dummy bar includes rotating the blank and the dummy bar about a horizontal axis.
 3. A method as claimed in claim 1, further includes the step of connecting a power supply source to the blank being remelted, the blank being employed as a consumable electrode.
 4. A method as claimed in claim 1, further includes the step of connecting a power supply source to the blank being remelted by way of a non-consumable electrode being coupled to the power supply. 